Protesters have clashed with police outside the Syrian embassy in London just hours after demonstrators were arrested for storming into the building.

Crowds gathered in Belgrave Square, central London, on saturday afternoon, hurling rocks and bottles at the premises, amid reports of more than 200 people killed in a deadly barrage in the city of Homs.

The latest clashes follow the arrest of six people at the embassy overnight. Five were arrested for breaking into the building while one was held for assaulting a police officer. Two officers were taken to hospital with minor injuries.

The protest in London came as demonstrators forced their way into four other Syrian embassies in European and Middle Eastern cities.

In London, officers fought back a surge towards the embassy as crowds forced their way through barricades towards police in riot gear. Shouts of "free Syria" and "we want to close the embassy" rang out in protest against the Damascus regime's brutal repression of the country's uprising.

As passions flared, protesters climbed on top of barriers before police reinforcements arrived in large vans and the demonstrators were driven back across the road.

The Foreign Office condemned the violence and said that police were reviewing security arrangements at the embassy.

In Egypt, enraged Syrians again stormed the embassy in central Cairo, smashing furniture and equipment and setting fire to parts of the building. Hundreds of demonstrators gathered at a police station a few streets away to demand the release of six Syrians who they said were detained during the protest at the mission.

In Kuwait, witnesses said demonstrators stormed the Syrian embassy compound, breaking windows, tearing down the Syrian flag and hoisting the colours of the opposition movement.

Ronan McNern, a supporter of the Occupy London movement, attended the London protest overnight. He said there were 150 protesters surrounded by a ring of about 60 police officers, carrying truncheons.

He added that protesters "kept their spirits up" by singing, dancing and playing drums, while some waved Syrian flags.

The UN security council is meeting today to take up a much-negotiated resolution backing an Arab League peace plan for Syria.

At least 5,500 people have died in the country since pro-democracy campaigners took to the streets last year protesting against President Bashar al-Assad's regime.